[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[APD] RE: Aquatic-Plants Digest, Vol 5, Issue 20
Date: Tue, 06 Jan 2004 08:35:49 -0800
From: Wright Huntley <whuntley at verizon_net>
Subject: [APD] Re: LED lighting update
To: Aquatic Plants Digest <aquatic-plants at actwin_com>
Some folks get high on the damndest substances! :-) [BTDTBTWW!]
LOL yes... Yes I do :) what the heck does btdtbtww mean?
OK, so our new rule of thumb is 16 LEDs per 2G or 8 LEDs/G? :^) [A 55G
tank could get mighty expensive!]
No - I used 12 LEDs for adequate coverage with the LEDs I had - then 4 Reds
to compensate for the super blue light output. As soon as I get the new LEDs
I'll be switching to probably 4-5 1w whites, Tho I may have another array of
red/blue to play with to see how plant growth compares.
One of my next projects will be on a 10g to work out the whole WPG issue and
do some comparisons. Eventually we'll figured out some efficiency numbers -
in theory I could go super efficient and use 670nm 625nm and 470nm LEDs -
putting all the light in the plants light requirements; I could focus the
light exactly where its needed. Then the efficiency would be WAY beyond what
any current technology could manage - but that's not my goal.
Nothing says you can't immerse the ends of the plastic lenses in the
tank water. That should give a big spread, and increase efficiency a bit
in the process.
Actually my whole array can be dunked - its totally encased in epoxy - It's
landed in the fish tank a few times now with no ill effects (I haven't been
worried about reaching in to grab it out either). I'll test out some dry vs
wet comparisons with a single LED.
One question: How much total power are you using, and what percentage of
that is being dissipated in the resistors? The resistive heat and power
could probably be saved with a simple switching, current-regulated
supply. I have a hunch that one of the real benefits of LEDs is that the
efficiency could eventually be higher than incandescent and that those
of us with warm summers might like the "cooler" lamps. That will
probably never happen with resistors as ballast (voltage-to-current
converters), and voltage-regulated power sources.
[Almost as silly as buying 800psi CO2 when what we need is usually less
than 1 psi!]
I don't have a clue as to how to work out what you're asking - I'm not a
tech geek - just a redneck with occasionally too much time on my hands
(Scared yet?) :) I'm using an old computer AT power supply for a 12v feed,
I'm going to have to rethink resistors today - came home to a burnt out
board (the other shows 4.1v drop at each led - 144ma total draw from the
board (6 LEDs) should be well within specs - since Vmax is 4.5v and If is
30mA). Tony's idea of running a 3v wall wart - and running all the LEDs in
parallel is sounding better - maybe I'll just blow some real cash and buy a
The new MSN 8: advanced junk mail protection and 2 months FREE*
Aquatic-Plants mailing list
Aquatic-Plants at actwin_com